Why Do Lipid Transfer Protein-Hypersensitive Patients Tolerate Bean (and Other Legumes)?

• Published in: International archives of allergy and immunology Vol. 137; no. 3; pp. 236 - 240
• Main Authors: Asero, R., Mistrello, G., Roncarolo, D., Amato, S., Falagiani, P.
• Format: Journal Article
• Language: English
• Published: Basel, Switzerland Karger 01.07.2005; S. Karger AG
• Subjects: Allergies; Antigens, Plant; Biological and medical sciences; Carrier Proteins - immunology; Enzyme-Linked Immunosorbent Assay; Fabaceae - immunology; Food Hypersensitivity - epidemiology; Food Hypersensitivity - immunology; Fundamental and applied biological sciences. Psychology; Fundamental immunology; Humans; Immune Tolerance; Immunoglobulin E - immunology; Immunology; Immunopathology; Legumes; Lipids; Medical sciences; Original Paper; Plant Proteins; Proteins; Heat stability; Food allergy; Cross-reactivity; Lipid transfer protein; Bean; Human; Immunopathology; Legumes; Immunology
• ISSN: 1018-2438; 1423-0097
• DOI: 10.1159/000086336

Background: Patients allergic to nonspecific lipid transfer protein (LTP) frequently score positive on SPT with legumes but virtually never report adverse reactions eating these foods. Objective: This study investigated the IgE reactivity to legumes of LTP-allergic patients and aimed to establish whether legumes can be considered safe in LTP-allergic patients. Methods: Skin reactivity as well as clinical allergy to bean and pea were evaluated in a large cohort of LTP-hypersensitive patients. Sera from 12 patients showing clinical allergy to a number of botanically unrelated plant-derived foods and high levels of IgE to peach LTP were employed in in vitro studies (ELISA, ELISA inhibition, SDS-PAGE/immunoblot) aiming to investigate IgE reactivity to bean. Results: Preabsorption of patients’ sera with boiled bean extract did not cause any loss of IgE reactivity to peach LTP (whereas boiled apple totally abolished it). Immunoblot analysis did not show any IgE reactivity to bean proteins at about 10 kDa, and the SDS profile of bean showed little or no staining at 10 kDa. Conclusion: Sera from LTP-allergic patients do not seem to show any IgE reactivity to 10-kDa proteins in bean. Whether this is caused by epitopic differences between Rosaceae and bean LTPs or by the fact that LTP is not expressed in bean remains to be established. This study explains why virtually all LTP-allergic patients tolerate legumes and suggests that these foods should be considered safe for patients sensitized to this protein.